Mobile communication services provide functions such as wireless Internet access, VoD (Video on Demand) service, text and multimedia message transmissions, and on-line gaming.
The VoD service uses a media player to display packets transferred from a server using a streaming method. When a user accesses the VoD service, a server (e.g., content server) provides content (e.g., content packets) requested by the user, and the mobile station delivers the received content packets to the media player to display the content, in real time.
FIG. 1 is a flow diagram illustrating a VoD channel switching method, according to a related art.
Referring to FIG. 1, to receive a VoD service using the mobile station, the user connects to the content server using the mobile station. The content server transmits lists of content (e.g., channel lists) to the mobile station (S110). The mobile station arranges the channel lists and displays the channel lists on a display screen. The user selects desired content to receive from the channel lists (S112).
In the step S112, after the user selects the content, the mobile station drives a media player to connect to a Uniform Resource Locator (URL) of the selected content. Once the mobile station connects to the URL, the mobile station transmits a start command to the content server to allow the content server to transmit a content packet (e.g., a packet containing the selected content) (S114).
After the content server receives the start command through the URL, the content server transmits the selected content via the content packet(s) using a Real Time Streaming Protocol (RTSP) or a Real Time Protocol (RTP). The mobile station then displays the received content on a display screen, in real time (S116).
When the mobile station displays the selected content, if the user does not press a channel-switching key (e.g., channel up/down key and/or direction key), the content being currently displayed continues to be displayed (S120). After the selected content is completely displayed, the mobile station re-displays the channel lists on the display screen to enable the user to select other content (S120 and S122).
If the user wants to receive other content while the present content is being displayed and therefore presses the channel-switching key to select new content, the mobile station transmits a message to inform the content server to terminate transmission of the present content packet(s) (S124). Then, when a connection to the URL associated with the new content is obtained, the mobile station transmits a start command to the content server to allow the content server to transmit the packet associated with the new content (S114).
After receiving the respective transmission termination command and the transmission start command, the content server stops transmission of the present content packet(s), and starts transmission of the new content packet(s). The mobile station, in turn, receives the new content packet(s) and displays the new content on the display screen (S114 and S116).
However, the content server requires sufficient time to recognize and perform the commands transmitted from the mobile station. Thus, if the user frequently switches channel lists in less time than a command processing time, or, if the mobile station transmits plural commands, the content server may not have the required time for processing such commands. Therefore, many commands may be lost.